Audio desynchronization and "silly" support answer...

uuderzo

Newbie Location: Italy Joined: Jul 15, 2010 05:12 Messages: 37 Offline

Solved by

Sep 10, 2010 04:32

Hi all!

I'm trying to synchronize a video clip with a music. I need to synch music beat with video clips transitions.

Well, I noticed that if I keep working on a limited time range (the transition) and repeatedly play, stop, rewind (place the cursor before the transition with a click), play etc... then the music is played with a different time shift at each play. To hear the actual synchronization i need to rewind a lot (10+ seconds).

Looks like there is some kind of audio buffer misalignment if the time range is restricted. This leads to near impossibility to synch video with music.

I wrote this to cyberlink support and they told me that i was working on a corrupted file or i have old audio drivers. Cannot tell anything on drivers, because last driver version is of last year (sony is not very active on drivers update). Speaking on file corruption, i think it's silly because everything works well. Moreover, i detected this "floating" desynch issue only on the ending part of the video. The starting part is perfect.

Any comments? Umberto

Kevin R.

Contributor Location: Deep in the Heart of Texas Joined: Aug 17, 2010 15:58 Messages: 320 Offline

Sep 10, 2010 12:42

Are you "Locking" your sound track while editing? When ever I make music videos, I will lock the audio track, then use frame rates to adjust the video if need be. The transitions also take up time that you have to account for. Saving the world, one goofy video and meme at a time.

uuderzo

Newbie Location: Italy Joined: Jul 15, 2010 05:12 Messages: 37 Offline

Sep 11, 2010 10:35

Well Kevin...

I don't really understand what you mean with "locking" soud track. I simply placed clips on video track and music on audio track then, trying to adjust a clip length to match the transition with the music beat, i found that each adjustment had no avail. the music was always out of synch.

Then i simply tried to play, rewind then play again on the time range of the transition and each time i heard a different music time-shift even without modifications!

Looks like that a local editing causes a "virtual" out of synch. I wrote "virtual" because i experienced this only by repeatedly playing the same time range. If I play everything from the start, the synch issue doesn't exist!

Then, to check my music/video synch, i need to modify clip length, then rewind lots of seconds (10+) and then i can hear the real music alignment.

It's annoying because it makes you feel stupid when each modification leads to inconsistent results....

Thank you! Umberto

Kevin R.

Contributor Location: Deep in the Heart of Texas Joined: Aug 17, 2010 15:58 Messages: 320 Offline

Sep 11, 2010 11:13

Umberto,
If you look on each section, there will be a lock symbol, by clicking on that it locks and unlocks that part, be it video, PiP,music, or whatever. This can help with time shifts etc.
Is the music you are adding from the original video or something else?
As far as the transitions, you can choose the duration you like, but when it comes to the actual video clips, you can slow or speed up the frame rate to get things like cymbal crashes, guitar strums, lip syncs etc.
I try to use small sections at a time as this seems to help me with mine.
I hope this helps a little. There are great editors here and I'm sure someone will be able to help you if this doesn't. Saving the world, one goofy video and meme at a time.

ynotfish

Senior Contributor Location: N.S.W. Australia Joined: May 08, 2009 02:06 Messages: 9977 Offline

Sep 11, 2010 14:10

Hi Umberto -

Part of the reason the support answer sounded "silly" is that the provider has almost certainly never attempted to do what you're doing.

Kevin has had some experience! The best teacher.

I'd definitely follow his suggestion of locking the audio track.

Techniques & tricks used for syncing music with clips/images depend very much on the style of music, & Kevin has given you a few:
1. working on a small section at a time
2. tweaking video speed by splitting clip into short segments to increase or decrease speed

A couple of other things that might help are:
3. expanding timeline to max, so that frame level adjustments can be made
4. use transitions only if necessary - & make them short! (less than 00:00:00:10). Every transition affects the overall duration. For punchy music, use none!

There probably are other ideas related to your choice of music, clips & images... but we don't know what those are.

Cheers - Tony
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uuderzo

Newbie Location: Italy Joined: Jul 15, 2010 05:12 Messages: 37 Offline

Sep 13, 2010 03:59

Kevin, Tony,

Now i understand what you're meaning with locking. Unlocked music track may be likely the issue, given that when you work on video clip lengths sometimes the music clip starting point "follows" the video clip adjustment...

Sure i'll try to lock the music! Hope this will speed up my workflow.

Anyway, some little "volatile" desync issue still exist... i mean apparent out of sync caused by lots of play/rewind of the same part of video clip (without modifications) ( support answered me "don't play/rewind too many times" ). This issue happens between videoclip track and music track.

And another strange out of sync issue can happen between the video and audio part of the same videoclip. Following the example of this youtube video

http://www.youtube.com/watch?v=eHTCBdUVD8k

i found that to fix this particular issue is enough to select all on video track, delete then undo the deletion operation. This operation appears to fix erroneous out of synch issues. Obviously it would be better if the issue will be fixed.

Greetings! Umberto

ynotfish

Senior Contributor Location: N.S.W. Australia Joined: May 08, 2009 02:06 Messages: 9977 Offline

Sep 13, 2010 04:35

Wow Umberto!

What a discovery. I've seen PD do some weird stuff, but that's one of the better ones. People - watch Umberto's (Edit: friend's) video!

Another "workaround" is to right click on the video clip & select "Split Audio". That very often resolves sync problems.

Cheers - Tony

This message was edited 1 time. Last update was at Sep 13. 2010 04:46

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uuderzo

Newbie Location: Italy Joined: Jul 15, 2010 05:12 Messages: 37 Offline

Sep 13, 2010 04:39

Well, Tony

It's not my video, just found it on youtube. I don't want to get credits for that

Anyway, I had the issue stated on the video. And also the guy who produced the video had. So, it's not ony into my mind

Greetings! Umberto

uuderzo

Newbie Location: Italy Joined: Jul 15, 2010 05:12 Messages: 37 Offline

Sep 14, 2010 03:58

About the music "local rew/play" desynchronization issue...

I found another thread speaking of it:

http://forum.cyberlink.com/forum/posts/list/13167.page

Looks like the cause of the issue is the mp3 format of the audio track. Maybe a variable bitrate mp3 causes local synch issues when continually rewind/play the same time range.

In my next project i'll try to convert to WAV to see if the issues goes away. Anyway, looks like there is a possible cause for Cyberlink guys to investigate.

Greetings! Umberto